Mebctjbial feinting subface



Dec. 15, 1931. A -R TR|5T i Re. 18,290

MERCURIAL PRINTING SURFACE Original Filed Oct. 5, 1926 c e W4 Snom/ton y llua-Fanald Tnls Snltls attac/@Wd manga/W -Relissued Dec. 15, 1931 ^UNITED. STATES PATENTl VOFFICE:

v ARTHUR RONALD TnxsT, or LoNDoN, ENGLAND, AssIGNoE, BY'MESNE ASSIGNMENTS, To PANTONE CORPORATION, or NEW Yonx, N. Y., A' conPouATIoN. or DELAWARE uEEcUuIAL PRINTING sUEEAcE original No. 1,665,000, dated Apru 3, 192s, sei-iai N0. 1s9,e51,`n1ea october 5, 192s, and in Great Britain November 5,1925. Application for reissue led November 4, 1930. Serial No.-493,445.

This invention relates to improvements in mercurlal printing surfaces and has for 1ts object the production 'of a truly planographic cesses in the plate, then a very thin layer of;

silver orgoldon to the copper and so on until the recesses are filled up. The reason for adopting this method of producing the mercurial composition was to enable said composition to have some ofthe characteristics of both copper and silver or gold amalgains and to be of a firmly adherent nature. The metal of which this printing plate was made was dened as being unaffected by mercury and nickel was referred to by way of example. In the industrial manufacture of such a plate difficulties have been encountered inasmuch as it has been found that the v presence of the smallest quantity of foreign vmatter or oxide remaining on the nickel prevents that intimate adhesion of the initial layer of copper to the nickel which' is necessary to maintain the layers in place after they have been treated with mercury. y Experiments have shown that the alternate layers of copper and silver or gold prevent udiffusion of the mercury from the amalgam to such a degree as to render unnecessary the use of a metal unaii'ected by mercury for supporting theamalguminpllace; further it has been found that small traces of etching fluid on a copper surface do not have such a deleterious eifect on the final result as when nickel is employed and although cleanliness is of importance, that cleanliness which is readily obtainable in an ordinary workshop by an average artisan is suilicientto obtain reliable and satisfactory printing plates to be obtained. 1

This invention consists in the formation of 'thickness of the layer of nickel a planographic printing plate having ink retaining areas and mercurial ink refusing areas, comprising an electrodeposited layer of metal with which mercury can amalgamate, an electrodeposited layer of a metal unaffected by mercury to which printin ink will adhere, recesses insuch last named ayer locally exposing the rst named layer, said recesses being lled with a plurality o alternately `electrodeposited films of two metalsl one of which forms a hard amalgam with mercury,whi lstthe other takes a high polish when treated. with mercury, a film of the last .named metal being outermost, and the sur face of the printing plate being treated with mercury so as to produce areas to which printing ink will not adhere.

'In the drawings Fig. 1 diagrammatically illustrates in section an im roved platen according to this invention be ore etching. l

Fig. 2 diagrammatically illustrates in section an improved plateaccording to this invnion after the resist lhas been locally app 1e Fig. 3 diagrammatically illustrates in section an improved plate according to this invention after etchlng.

Fig. 4c diagrammatically illustrates in section an im roved plate according to this invention a er the initial electrodeposit has been effected in the etched areas.

Fig. 5 diagrammatically illustrates tion an improved plate-according to this 1nvention after the alternate electrodeposits of copper and silver or silver and copper have been applied to the initial deposit, and

Fig. 6 diagrammatically illustrates in section the finished plate ready for mercurializm Te above figures are not strictly to scale and only serve the purpose of showin steps by which it is possibleto produce t e improved plate on an iron base.

Referring to the. drawings z is the iron base on which a layer'a of copper and a layer b of nickel have been electrodepeosited, the

one or one andone half one'thousandths part of one inch whilst the layer oflcopper may ing about be of equal thickness or more or less ithan this amount as may be found convenient.

Local resists c are applied to said nickel layer b in any suitable way and may be composed of what is known as burnt in enamel. The local resists c may be light sensitive bichromated fish glue enamel, and after the nickel surface is coated With this enamel, a

photo-print is taken from an irregular grain l or screened negat-ive, preferably by means .of a-point source of light. After exposure, the

.printing surface is Wash developed and baked in the well known manner. Portions of the nickel layer b are exposed in the nonprinting areas of the plate, the resist c remaining on thelplate in the printing areas. n

The exposed surface of the nickellayer b is then etched, by means of any suitablecorrosive fluid such as an iron chloride bath, until the copper layer a is exposed and etching may be continued until about one ten a protective covering. for the copper a inasvmuch as it has been found that if a thin layer ofi-copper or a metal having a greater ailinity for mercury than copper is electrodeposited on to an electrodeposited copper surface, the last electrodeposited metal layer or the interface between the layers to some extent prevents mercury diiusing into the copper previously electrodeposited. l g

vThis prevention of "dilfusion is probably dueto the fact that as copper is electropositive to silver or gold the intimate molecular interchange at the interface during the plating process produces actually or in eiect an alloy of metals having this peculiar characteristic. A Y

It has been found that satisfactory results are obtained if the thickness' of the layer e of copper, silver or gold is about one fifth Vof the total depth of a recessv d or about twenty five one hundred thousandths part of van inch.

Each lever e if ofsilver or gold has a layer f of copper electrodeposited thereon. said layer f being approximately equal in thickness to that of the layer e; but if the layer e is (f copper then the layerf is of silver or ol g As illustrated there are five layers in all of which g and h are of silver or gold and z' of copper the silver or gold and copper layers being alternately applied so as to ,reduce the diffusion to a minimum. 1 y

Obviously the'invention is not limited to ive'layersand any number of ,layers greater than two may beused provided that the last layer is of silver orgold so as to provide a polished nongranular face on mercurization.

By the use of the alternate layers of silver or gold and copper or copper and silver or gold not only is it possible to obtain a large number of interfaces but it is also possible to arran e that each of the Vrecesses d are exactly lled up so as to produce a planographic printing surface.

Those skilled in electrodeposition of metal into `recesses will recognize that it isV impossible to prevent a-ridge Ic building up around each recess and this is removed .by rubbing with polishing charcoal or very ne emery paper so that the printing surface is )and remains perfectly .planographic The non-printing parts of the printing surface are mercurialized by the application of mercury in a metallic state for example, and finally the resists c can be removed if so. de-Y link retaining areas and 'mercurial ink refusy '100 111g areas, comprising a base plate, an electrodeposited layer of metal with which mercury can amalgamate, an electrodeposited layer of a metal unaffected by mercury to which printing ink will'adhere, a recess or recesses pa'sslng through said last named layer so as lo' cally to expose the rst named layer, and a plurality of alternately electrodeposited filmsV of two metals in each recess one of said films forminga hard amalgam with mercury whilst the other iilm takes a high polish when treated with mercury, a film of the last named metal being outermost; the surface of the printing plate 'beingIl treated with mercury so4 as vto produce mercurial areas t0 which printing ink will not adhere. Y

3. A process for producing a planographic printing plate having ink retaining areas and mercurial ink refusing areas comprising Vthe electrolytic deposition of a layer of copper on to an iron base, the electrolytic deposition of a layer of nickel onto said layer of copper, the application'of a local resist to the nickel layer to protect the printing areas, the etching away of the unprotected parts of the nickel ayer to expose the copper layer and form a recess or recesses,the.electrolytic deposition on the exposed parts of the nickel and the copper of a thin layer of a noble metal, the electrolytic deposition of alternate thin layers of copper and a noble metal on to and the copper of a thin layer of copper, the

` electrolytic deposition of alternate thin layersV said thin layer so as to fill up said recess -or recesses and externaly present a surface of a noble metal,` and the external application of mercury to such thin layers.

4. A process for producing a planographic printing plate having ink retaining areas and mercurial ink refusingv areas comprising the electrolytic vdeposition of a layer of copper on to an ironbase, 'the electrolytic'deposition of a layer of nickelon to said copper layer7 the application of a localiresist to such nickel layer to protect the printing areas, the etching away of the unprotected parts of the nickel layer to expose the copper layer and form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel of a noble metal and copper onto said thin layer so as to lfill up said recess or recesses and externally present a surface of a noble metal, and the external application of Inercury to such thin layers.

5. -A process for producing aplanogi'aphic printing plate having ink retaining areas andmercurial ink refusing areas comprising the electrolytic deposition of a layer of copper one or one and one half one thousandths part electrolytic deposition ofa layer of nickel one or one and, one half one thousandths .part of an inch in thickness on to said copperlayer, the application of a local resist to said nickel layer to protect the printing areas, the etching away of the unprotected parts of the nickel layerto expose the copper layer and form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel and the copper 'o a thin layer of a noble metal, the electrolytic deposition of alternate thin layers of copper and a noble metal on to said thin layer so as to ill up said recess or recesses and externally present a surface of a noble metal, and the external application of mercury to such thin layers.

6. AA process for producinga planographic printing plate having ink retaining area-s and mercurial ink refusing areas comprising the electrolytic deposition of va layer of copper one or one and one hal-f one thousandths part.r of an inch in thickness on to' an iron base, the.

electrolytic depositicn of 'a layer of nickel one or one and one half one thousandths part of an inch in thickness on to said copper layer, the application of a local resist to said nickel layer to protect theprinting areas the etching away of the vunprotected parts of the nickel layer to expose the copper layer and penetrating the copper layerv for one ten tliousandth part of an inch to'form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel and the copperlof a thin layer off'a noble metal, the electrolytic deposition of alternate thin layers of copper and a noble metal on to said thin layer one or one and one half one thousandths part' of an inch in thickness on to said copper layer, the application of a local resist to said nickel layer to protect the printing areas, the

nickel layer to expose the copper layer and penetrating the co-pper layer for one ten thousandth part of an inch to form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel and the copper of a thin layer of copper, the electrolytic deposition of alternate thin layers of a noble metal '80 etching away of the unprotected parts of the and copper on to said thin layer so as to fill up said-recess or recesses and externally present a surface ofa noble metalrand the external application of mercury to such thin layers. of an lnch 1n thickness on to an iron base, the

8. A process for producing a planographic printing plate having ink retaining areas and mercurial inkrfusing areas comprising the -electrolytic deposition -of a layer of cop er on to aniron base, the electrolyticdepositlon of 'a layer of nickel on to said layer of copper, the application of a local resist to the nickel layer 'to protectthe printing areas, the etching away of. the unprotected parts of the nickel layer to expose the copper layer and,

form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel and the copper of a thin layer of silver', the electrolytic deposition of alternate thin layers of cop er and silver on to said thin layer so as to ll up said recess or recesses and externally present -a'surface of silver, and the external application of mercury "to such thin layers.

9. A process for producing a planographic printing plate having ink retaining areas and mercurial ink refusing areas comprising theelectrolytic deposition ofa layer of copper on to an iron base, the electrolytic deposition of a layer of nickel on to said copper electrolytic deposition of alternate thin layers of silver and copper on to said thir layer so as to fill up said recess orrecesses and externally present a surface of silver,

and the external application of mercury to such thin layers. I

10. A process for producing a planographic printing plate having ink retaining areas and mercurial ink refusing areas comprising the electrolytic deposition of a layer recess or resses,t

0f copper one or one and one half one vthousandths part of an inch in thickness on to an iron base,` the electrolytic deposition of a layer of nickel one or one and one half one thousandths part of an inch in thickness on to said copper layer, the application of al local resist to said nickel layer to protect the printing areas, the etching away of the unprotected parts of the nickel layer to expose the copper layer and form a recess or recesses, the electrolytic deposition` oh the exposed' arts 'of the nickel and the copper ol-a. thin w ayer of silver, the electrolytic deposition of alternate thin layers of copper and silver on to said thin layer so as to lill up saidv recess orrecesses and externally present a surface. of silver, and the external application of mercury to such thin layers. i

11. A process for producing a planographic printing plate having ink retaining areas and mercurial ink refusing areas comprising the electrolytic deposition of a layer'o copper one or/one and one half one thousandths part ofan inch in thickness on to an iron base, the electrolytic deposition of a layer of nickel one or one and one half one thouvsandths part of an inch in thickness on to said copper layer, the application of a local resist to said nickel layer to protect the print,- ing areas, the etchin away of the improtected parts of ther nic el layer to expose the copper layer -and to penetrate the copper layer for one ten thbusandth part of an inch to form a recess or recesses, the electrolytic deposition on the expose/d parts of the nickel and the copper of thin layer of silver, the electrolytic deposition of alternate thin layers of copper and silver on to said thin layer so as to fill up'said recess or recesses and excopper of a thin la er of copper, the electrolytic deposition o alternate thin layers of silver and copper'on to said thin layer so as to lill up said recess or recesses and externally present a surface of silver, and the external application of mercury to suchthin layers.

13. A planographic printing plate having ink-retaining' and mercurial' lnk-refusing areas, comprising a base plate, and an elec- .trodeposited layer of metal with which mercury can amalgamate and ain electrodeposited layer of a metal unaffected by mercury to which printing ink will adhere, a recess or recesses passing through said last named layer so as locallyto expose the first named layer and a firmly adherent electrodeposited and amalgamated layer of precious metal in each recess. c

14. A planographic printing plate having ink-retaining and v mercurial ink-refusing areas, comprising a base plate, and an electrodeposited layer of metal with which mercurycan amalgamate and an electrodeposited layer of a metal unaiected by mercury to which printing ink will adhere, a recess or recesses-passing through said last named layer so as locally to expose the first named vlayer and a firmly adherent electrodeposited and amalgamated layer of silver inl each recess. Y

In Witness whereof I have hereunto set my hand this 24th day of October, 1930.

l l A.VRONALD TRIST.

ternally present a. surfacevof silver, and the 4 external application of mercury to such .thin layers.

12. A process for producing a planographic printing plate having ink retaining areas and'mercurial ink refusing areas comprising the electrolytic de osition of al la er of co per one or one an one half one-t ousandt s art of an inch in thickness. on to an iron ase, the electrolytic deposition of a layer of nickel one or one and one half one thou- 'sandths part of an inch in thickness on to said copper layer, they application of a llocalresist to said mckll'ayer to protect lthe prmting areas, vthe etching away of the unprotected arts of the nickel layer to expose the copper ayer and to. penetrate the copper layer for one ten thousandth art of an inch to form a Ke electrolytic.depositionY on the parts of the 'nickel vand the 

